前后数据传输协议规范

在进行增删改操作时，我们通常会返回true或false来表示是否查询成功

在进行查询单条数据时，我们通常返回一个json串对应当前查询数据

在进行查询全部数据时，我们通常返回一个json数组

这样就出现了一个问题：返回的数据种类太多，没有一个统一的格式，前端无法清楚的获取当前返回数据的类种类。

为了解决这种现象，我们可以自己规定一个统一的返回格式

data：存放数据层返回的数据

code：告知前端调用了何种方法

msg：告知用户查询结果 

在controller层里新建一个Result类，用来规定统一返回格式

在新建一个Code类，规定各种请求方法的状态码

package com.brrbaii.controller;
 
public class Code {
    //请求成功
    public static final Integer SAVE_OK = 20011;
    public static final Integer DELETE_OK = 20021;
    public static final Integer UPDATE_OK = 20031;
    public static final Integer SELECT_OK = 20041;
 
    //请求失败
    public static final Integer SAVE_ERR = 20010;
    public static final Integer DELETE_ERR = 20020;
    public static final Integer UPDATE_ERR = 20030;
    public static final Integer SELECT_ERR = 20040;
}

我们在controller里将所有的方法的返回类型都修改为Result类

将数据层的返回结果作为data参数

判断请求类型的操作状态码获取code

将code和data两个数据作为构造器参数构造Result对象，并将该对象返回成一个我们定义的规范的统一的Json格式

 附上完整代码

Controller层：

package com.brrbaii.controller;
 
import com.brrbaii.pojo.Brand;
import com.brrbaii.service.BrandService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
 
import java.awt.print.Book;
import java.util.List;
 
@RestController
@RequestMapping("/brands")
public class BrandController {
    @Autowired
    private BrandService brandService;
    @GetMapping
    public Result getAll(){
        List brands = brandService.selectAll();
        Integer code = checkMesg(brands) ? Code.SELECT_OK : Code.SELECT_ERR;
        return new Result(code,brands);
    }
 
    @GetMapping("/{Id}")
    public Result getById(@PathVariable Integer Id){
        Brand brand = brandService.selectById(Id);
        Integer code = checkMesg(brand) ? Code.SELECT_OK : Code.SELECT_ERR;
        String msg = checkMesg(brand) ? "查询成功": "查询失败";
        return new Result(code,brand,msg);
    }
 
    @PostMapping
    public Result save(@RequestBody Brand brand){
        boolean flag = brandService.save(brand);
        Integer code = flag ? Code.SAVE_OK : Code.SAVE_ERR;
        return new Result(code,flag);
    }
 
    @DeleteMapping("/{Id}")
    public Result delete(@PathVariable Integer Id){
        boolean flag = brandService.delete(Id);
        Integer code = flag ? Code.DELETE_OK : Code.DELETE_ERR;
        return new Result(code,flag);
    }
 
    @PutMapping()
    public Result update(@RequestBody Brand brand){
        boolean flag = brandService.updateById(brand);
        Integer code = flag ? Code.UPDATE_OK : Code.UPDATE_ERR;
        return new Result(code,flag);
    }
 
    public boolean checkMesg(Object o){
        return o != null ? true : false;
    }
 
}

Service接口：

package com.brrbaii.service;
 
import com.brrbaii.pojo.Brand;
 
import java.util.List;
 
public interface BrandService {
 
    List selectAll();
 
    Brand selectById(Integer Id);
 
    boolean save(Brand brand);
 
    boolean delete(Integer Id);
 
    boolean updateById(Brand brand);
}

Service实现类

package com.brrbaii.service.Imp;
 
import com.brrbaii.dao.BrandDao;
import com.brrbaii.pojo.Brand;
import com.brrbaii.service.BrandService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
 
import java.util.List;
 
@Service
public class BrandServiceImp implements BrandService {
 
    @Autowired
    private BrandDao brandDao;
 
    @Override
    public List selectAll() {
        List brands = brandDao.selectAll();
        return brands;
    }
 
    @Override
    public Brand selectById(Integer Id) {
        Brand brand = brandDao.selectById(Id);
        return brand;
    }
 
    @Override
    public boolean save(Brand brand){
        return brandDao.save(brand);
    }
 
    @Override
    public boolean delete(Integer Id) {
        return brandDao.deleteById(Id);
    }
 
    @Override
    public boolean updateById(Brand brand) {
        return brandDao.updateById(brand);
    }
}

 Dao层：

package com.brrbaii.dao;
 
import com.brrbaii.pojo.Brand;
import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.ResultMap;
import org.apache.ibatis.annotations.Select;
import org.springframework.stereotype.Repository;
 
import java.util.List;
 
@Repository
public interface BrandDao {
 
    @Select("select * from tb_brand")
    @ResultMap("BrandResult")
    List selectAll();
 
    @Select("select * from tb_brand where id = #{Id}")
    @ResultMap("BrandResult")
    Brand selectById(Integer Id);
 
    @Delete("delete from tb_brand where id = #{Id}")
    boolean deleteById(Integer Id);
 
 
    boolean save(Brand brand);
 
    boolean updateById(Brand brand);
}

BrandDao.xml（用来写复杂的sql语句）：

"1.0" encoding="UTF-8" ?>
mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
 
<mapper namespace="com.brrbaii.dao.BrandDao">
    <resultMap id="BrandResult" type="brand">
        <result column="brand_name" property="brandName" />
        <result column="company_name" property="companyName" />
    resultMap>
 
    <insert id="save">
        insert into
            tb_brand
        values
           (null, #{brandName}, #{companyName}, #{ordered}, #{description}, #{status})
    insert>
 
    <update id="updateById">
        update tb_brand
        <set>
            <if test="brandName!=null and brandName!= ''">
                brand_name = #{brandName},
            if>
            <if test="companyName!=null and companyName!= ''">
                company_name = #{companyName},
            if>
            <if test="description!=null and description!= ''">
                description = #{description},
            if>
            <if test="ordered!=null and ordered!= ''">
                ordered = #{ordered},
            if>
            <if test="status!=null and status!= ''">
                status = #{status},
            if>
        set>
        where id = #{id}
 
    update>
 
mapper>

POJO实体类：

@Data
@NoArgsConstructor
@Getter
@Setter
@ToString
public class Brand {
    private int id;
    private String brandName;
    private String companyName;
    private int ordered;
    private String description;
    private int status;
 
}

 

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